This study will be involved with levels of metabolites and enzyme activities closely associated with glutathione oxidation/reduction and the pentose shunt. For example, ascorbic acid levels and the activities of glutathione peroxidase, glutathione reductase and glucose-6-phosphate dehydrogenase will be measured. Corneal endothelial tissue cultures will be used to supplement bovine eyes as a tissue source. Corneal epithelium as well as endothelium will be investigated since the former tissue probably cooperates in some way with hydration control. Other metabolites, such as adenosine, will also be investigated. Ultimately the study will concern as adenosine, will also be investigated. Ultimately the study will concern itself with possible interactions of these metabolites with Na-K-ATPase and/or other cell wall sulfhydryl interactions. It is at that stage that certain reagents (i.e., drugs, chemicals) might be tested for usefulness in controlling hydration.